RSA-SHA1 signature method. The RSA-SHA1 signature method uses the RSASSA-PKCS1-v1_5 signature algorithm as defined in RFC3447
section 8.2 (more simply known as PKCS#1), using SHA-1 as the hash function for EMSA-PKCS1-v1_5.

The Signature Base String is signed using the Consumer’s RSA private key per RFC3447 section 8.2.1, where K is the Consumer’s RSA private key,
M the Signature Base String, and S is the result signature octet string:

S = RSASSA-PKCS1-V1_5-SIGN (K, M)

oauth_signature is set to S, first base64-encoded per RFC2045 section 6.8, then URL-encoded per Parameter Encoding.

sign

The Signature Base String is signed using the Consumer’s RSA private key per RFC3447 section 8.2.1, where K is the Consumer’s RSA private key,
M the Signature Base String, and S is the result signature octet string:

S = RSASSA-PKCS1-V1_5-SIGN (K, M)

oauth_signature is set to S, first base64-encoded per RFC2045 section 6.8, then URL-encoded per Parameter Encoding.

verify

Verify the signature of the given signature base string. The signature is verified by generating a new request signature octet string, and comparing it
to the signature provided by the Consumer, first URL-decoded per Parameter Encoding, then base64-decoded per RFC2045 section 6.8. The signature is
generated using the request parameters as provided by the Consumer, and the Consumer Secret and Token Secret as stored by the Service Provider.